Method and apparatus for rolling thin sheetlike material



METHOD AND APPARATUS FOR ROLLING THIN SHEET mm MATER L E K c E T S R EAL Original Filed June 30 1923 4 Sheets-Sheet l e T hn ct. A. P. STECKEL LWQJQS METHOD AND APPARATUS FOR ROLLING THIN SHEET LIKE MATERIAL Oct, 21; 1930. A. P. STECKEL 1,779,195

METHOD AND APPARATUS FOR ROLLING THIN SHEET LIKE MATERIAL originalFiled June 30, 1925 4 Sheets-Sheet 3 INVENTOR mm. 9

0d, 21, 1930. A. P. STECKEL 1,779,395

METHOD AND APPARATUS FOR ROLLING THIN SHEET LIKE MATERIAL Original Filed June 50, 1925 4 SheetsSheet 4 INVENTOR Patented Oct. 21, 1930 UNITED STATES PATENT OFFICE ABRAM I. STECKEL, OF YOUNGSTOWN, OHIO, ASSIGNOR TO THE COLD METAL PROCESS COMPANY, OF YOUNGSTOWN, OHIO, A CORPORATION OF OHIO METHOD AND APPARATUS FOR ROLLING THIN SHEETLIKE MATERIAL Original application filed .Tune 30, 1923, Serial No. 648,761, and in Canada December 28, 1927. Divided and this application filed December 9, 1929.

This application is a division of my application Serial No. 648,761, filed June 30, 1925:. The invention relates to an improved rolling mill and method of rolling whereby superior results are obtained. It applies particularly to the rolling of thin sheet-like material in long lengths. It provides a mill which may be operated at high speedsand permits of rolling metal strips of practical- 1y unlimited length. In cold rolling I have successfully operated a mill of the character herein disclosed at speeds up to 1200 feet per minute.

My application above recited and my application Serial No. 200,227, filed June 20, 1927, as a continuation-in-part of said application Serial No. 648,761, relate particularly to a method of rolling wherein a substantial portion of the power required is supplied through tension on the delivered strip. \Vhile the invention of the present application is of great value in such combination, the advantages of the present nvention may be obtained in rolling wherein the power is not supplied through tension on the delivered strip. It is especially useful 1n the rolling of metal of great thinness relatlve to its width.

I provide working rolls having back ng rolls of larger diameter and anti-fraction mounting for said backing rolls of a character adapted to Withstand the rolling pressures encountered and the high speeds which are employed. In a preferred form of the. invention the backing rolls are provided with necks which carry the anti-friction bearings, these necks being of sufficient size to W1thstand the rolling pressure, and the diameter of the backing roll body relative to the diameter of the Working, roll being of exaggerated size so as to permit of using antifriction bearings of sufficient size for the conditions encountered. It is important that the bearings be of adequate size and of proper character, and in the form of the lnvention herein particularly described, roller bearings employing spaced-apart rollers are used.

Priorto my invention it was generally considered impossible to cold roll at speeds in excess of 150 to 200 feet per minute, whereas Serial No: 412,742.

by the term high speed I contemplate speeds several times this figure, or in the order of multiples of the speeds commonly employed. In hot rolling fairly high speeds have been employed in the manufacture of extremely narrow material. In such case the roll neck bearings have been subjected to only rela- I to Withstand the rolling pressure over extended periods of time, it is desirable that the backing roll necks be at least as large, and preferably larger, than the working roll bodies. The backing roll bodies are larger than the necks thereof in an amount sufficient to provide adequate space for the anti-friction bearings.

Anti-friction bearings of the proper character will operate continuously with but little temperature rise. They therefore limit the frictional resistance of the backing rolls to rotation below a point where the active pass contour is adversely afi'ected. \Vhere the roller bearings are applied to the backing roll necks they eliminate the heating of such necks, which heat adversely affects the shape of the working roll body. Stated in another way, the antifriction hearings on the necks are effective for limiting the rise in temperature of such necks to such a point that variations in the contour of thebacking rolls are controlled within such limits as to substantially prevent buckling or wrinkling of the thin material passed between the working rolls.

It will be understood that in a backed up mill, the working rolls, being relatively small, are supported by the backing rolls, and any change in the contour of the backing roll will change the contour of the pass, since the 0 Work rolls, being relatively small, will adapt themselves under the high pressures encountered in rolling to the contour of the backing rolls. \Vhere the contour of the backing rolls changes to such extent that the material is unduly thinned on the edges, wrinkling or rufiling of the edges results. If the material becomes too thin in the middle, buckling of the material is caused.

My invention is also highly advantageous in that the amount of power required is markedly reduced, and the antifriction bearings are so situated that they are amply protected, being a considerable distance removed from the actual pass. They are not afiect-ed by grease, scale, dirt or water, if any of these be present at the point where the working rolls engage the material.

If desired, a plurality of stands may be employed. In such case they are preferably arranged in line so that two or more stands will engage the material at the same time. By reason of the fact that the material elongates in each pass the last stands in a continuous mill pass a very long strip in the same length of time as a much shorter strip was passed through the first few stands. By the use of my improved mill these high speeds may be readily attained and this with relatively low power requirements.

A great advantage of the design is that the backing rolls can be given any desired diameter without affecting the power required to operate the mill. It is therefore possible to employ large backingrolls, thus permitting the use of adequate anti-friction bearings, whereas in wide two-high mills for rolling material of substantially uniform thickness there is not su fficient space to accommodate anti-friction bearings which will carry the load; this because in the rolls of a two-high mill the necks of the rolls would have to be so large in order to resist theseparating force that there would be insufficient space between them for adequate roller bearings.

I prefer to employ backing rolls whose diameter is at least twice the diameter of the working rolls, as this permits, in a mill of proper design in the practical range of sizes, of using roller bearings of such size that they will last indefinitely under the severe conditions of service. This ratio should be materially increased for high speed cold rolling, because of the much greater pressures encountered. Also, if it is desired to produce a product which is practically free from heavy center or crown, the ratio of backing roll diameter to working roll diameter should be considerably greater than 2.

For example, in cold rolling steel 7 inches wide by .001 inches thick, I have successfully produced material having a crown less than .0001 inches in a mill having a ratio of backing roll diameter to working roll diameter of 10, the backing rolls being 20 inches in diame ter and the working rolls being 2 inches in diameter. I have also successfully rolled steel 16 inches wide by .002 inches thick with a center crown of less than .0001 in a mill where the ratio was 8, the backing rolls being 24 inches in diameter and the working rolls ing the material to track through the center of the mill.

Roller bearings of the proper type and of adequate size do notwear perceptibly, whereas in strip mill practice where the width ofthe strip is greater than the narrowest widths the brasses wear at such a rate that it is practically impossiblein thin material to keep the several stands in adjustment at high speed.

In the accompanying drawings, illustrating the present preferred embodiment of my invention for rolling with the material under tension both in a single stand and in a continuous mill,

Figure l is a diagranm'iatic view illustrating my improved mill;

Figure 2 is a vertical longitudinal section through such mill;

Figure 3 is a horizontal section taken on the line IHTH of Figure 2;

Figure 4: is a vertical transverse section taken on the line IV1V of Figure 2, and showing the mechanism for actuating a reel employed;

Figure 5 is an end View of the mechanism shown in Figure 4;

Figure 6 is a view showing a portion of Figure 4 and taken on the section ViiVi;

Figure 7 is a detail perspective view showing part of the control mechanism for a reel;

Figure 8 is a diagrammatic view of a continuous mill; and- Figure 9 is a detail view showing diagrammatically the driving of the working rolls in the mill of Figure 8.

The mill shown in Figures 1 to 7 inclusive comprises working rolls- 2 provided with backing rolls 3 of materially larger diameter. These backing rolls are more than strong enough to withstand the force tending to separate the working rolls during rolling, and are provided with large diameter necks 4. As shown in Figure l, the necks of the backing rolls are of larger diameter than the bodies of the working rolls 2. The necks 4 extend into cases 5 for roller bearings 6. As best shown in Figure 2, the rollers are spaced apart, as, for example, by cages of any desired construction so that the rollers do not rub against one another and are not in danger of getting out of alinement. The cases 5 are carried in the windows of mill housings 7 and the setting of the rolls is controlled by screw-downs 8.

The large diameter of the backing rolls 3 permits of using the large diameter anti friction bearings illustrated in Figure 2,

ported by the castor rollers 11.

whereas of the backing rolls were simply strong enough to withstand the spreading force it would bediflicult, if not impossible, to fit a long lived bearing into the space thus left available. 1

As previously stated, the mill herein illustrated is of a character wherein the power for driving is supplied through tension on the delivered strip. In Figure 1, the metal strip S is fed through the mill first in one di rection and then in the other, the ends of the strip being connected to reels 9 and 10, these reels being alternately employed as tension and paying out reels. In this form of the invention neither the work rolls nor the backing rolls are driven, the working rolls being in the form of plain cylinders and being sup- The castor rollers 11 for the upper work roll are carried on shafts 12 mounted in brackets 13, while the corresponding castor rollers for the lower working roll are mounted on stop shafts 14 carried in brackets 15.

The mounting and driving of the reels 9 and 10 is best shown in Figures 2 and 4 to 7 inclusive. The reels are carried on shafts 16 journaled in standards 17, these standards being held in spaced relation with the mill housings by spreader arms 18. Each reel freely rotatable on its shaft 16. Gears 19 are keyed to the shafts 16 and each of them meshes with a pinion 20 connected to any suitable source of power. Each gear 19 is provided with a pawl 21 adapted to mesh with ratchet teeth 22, formed on the reel proper.

The pawl 21 is shown in detail in Figure 7. The pawl finger 21 is formed integral with a rock shaft 21 which is journaled in the gear 19 and carries on its outer end an arm 21. A spring 23 normally urges the pawl finger into engagement with its ratchet teeth, but when it is desired to disengage the pawl from the ratchet a slide 24, carried in a centrally-bored opening 25 in the shaft- 16, is pushed inwardly. The slide is provided with a cam face 26, which face engages the lower end of a push rod 27 engaging the arm 21. At its upper end the cam face 26 has a flat portion 28 and when the push rod 27 rides onto this flat face, the pawl is held out of engagement with the ratchet. The construction of each of the reels is the same, andin operation the slides 24 are alternately pushed in and pulled out so as to alternately connect the reels 9 and 10 to the driven pinion 20.

The strip S is connected to the reels in any desired way. In Figure 2 there is shown a leader strip 29 which is connected to the metal strip S at 30. Figure 2 shows a sheave ivheel 31 around which the material travels to reach the bottom reel 10.

In the mill shown in Figure 8, there are a plurality of stands such as those illustrated the strip is entered in all the mills.

compound wound where it is desired to drive the mills principally by tension on the delivered strip, these motors having a drooping speed characteristic such that they will divide up thework among themselves after Motors of this character, in which the torque tends to vary inversely with the speed, are well known and need not be described in detail. As illustrated in Figure 8, the shunt winding of each motor is provided with a rheostat 44 for adjusting the motor speed as desired. The motor 45 for the reel 41 is of similar character.

Since the stands are of the character shown in Figure 2 there is ample room to let the neck or the wobblers of the working rolls extend out through the windows of the houslngs 7 I have illustrated and described the pres- I cut preferred embodiment of my invention, both in the single and continuous mills, and wherein the power is supplied principally or entirely by tension on the delivered strip. It will be understood, however, that the invention is not limited to such forms but may be otherwise embodied or practiced within the scope of the following claims.

I claim:

1. In the method of rolling thin sheet or strip material in a mill having working rolls, and backing rolls, of larger diameter, for the working rolls, the steps consisting in limiting the rise in temperature of the backing roll necks to such a point that variations in the contour of the backing rolls are controlled within such limits as to substantially prevent buckling or wrinkling of the thin material passed between the working rolls.

2. In the method of rolling thin sheet or strip material in a mill having working rolls, and backing rolls, of larger diameter for the working rolls, the steps consisting in supply ing rolling power through the working rolls and limiting the rise in temperature of the backing roll necks to such a point that variations in the contour of the backing rolls are controlled within such limits as to substantially prevent buckling or wrinkling ofthe thin material passed between the working rolls.

3. A mill for rolling material of substantially uniform thickness, comprising at least two working rolls provided with backing rolls of larger diameter, the backing rolls having necks of suflicient size to withstand the 'rolling pressure, and anti-friction bearand of a character to permit of rolling at speeds high relative to those ordinarily employed.

4. A mill for rolling material of substantially uniform thickness, comprising working rolls provided with backing rolls of lar er diameter, the backing rolls having nec s of sufiicient size to withstand the rolling pressure, anti-friction bearings for said backing roll necks, the diameter of the backing roll body relative to the diameter of the working roll being such as to permit of using anti-friction bearings of sufiicient size to withstand the rolling pressure, said antifriction bearings being of a character to Withstand operation at speeds which are high relative to those ordinarily employed, a working roll having a neck extending between the anti-friction bearings of the backing rolls, and means for supplying rolling power through the working roll neck.

5. In the method of rolling thin sheet or strip material in a mill having working rolls provided with backing rolls of larger dlameter, the step consisting in maintaining the temperature of the backing roll necks below a pointwhere expansion of a backing roll body induced by heat in the roll necks causes variation and consequent buckling or wrinkling of the product.

6. A mill for rolling thin strips or sheets,

' having working rolls and backing rolls of larger diameter, the working rolls being substantially uniformly spaced apart and defining a pass of such width and thlnness that material heating of the backing roll necks would cause such unequal expansion of a backing roll body as would distort the pass sufficiently to cause buckling or wrinkling of the thin product, and anti-friction bearings for the backing rolls, whereby the temperature of the backing roll necks is maintained sufliciently low to substantially obviate such unequal expansion as would cause such buckling or wrinkling.

7. A rolling mill for material of substantially uniform thickness, the mill being of such width that the available space 1n a two high mill of the same width would prevent the use of roller bearings of the necessary load carrying capacity, comprising large backing rolls with necks, intermediate work: ing rolls, means for driving the working rolls, and anti-friction bearings for the backing rolls,- the anti-friction bearings havlng outer races encircling the necks and being of such character as to withstand speeds which are high relative to those ordinarily employed, the intermediate working rolls being of sufficiently small diameter to reduce the spreading force in the mill to such point that the anti-friction bearings employed require a smaller space than those which would be required in a two high mill of the same width, whereby the outer races of the bearings for the backing rolls are sufficiently spaced apart to allow room for the driving means.

-8. A continuous mill for rolling material of substantially uniform thickness, comprising a plurality of stands having working rolls provided with backing rolls of larger diameter, the backing rolls having necks of sufficient size to withstand the rolling pressure, and anti-friction bearings for said backing roll necks of a character to withstand speeds which are high relative to those ordinarily employed, the diameter of the backing roll bodies relative to the diameter of the working rolls being such as to permit of using anti-friction bearings of suflicient size to Withstand the rolling pressure, the stands being so arranged that during at least a portion of the rolling operation the material is being rolled simultaneously in at least two stands.

9. In the method of rolling material of substantially uniform thickness in a mill comprising a plurality of stands having working rolls provided with backing rolls of larger diameter, the steps consisting in passing a piece of material through the mill so that during at least a portion of the rolling operation it is being rolled simultaneously in at least two stands, and maintaining the temperature of the backing roll necks below a point where expansion of a backing roll body induced by heat in the roll neck causes detrimental variation in the product.

10. In the method of rolling thin material of substantially uniform thickness in a continuous mill comprising a plurality of stands having working rolls and backing rolls of larger diameter, the steps consisting in passing material successively through the several stands and limiting the rise in temperature of the backing roll necks to such a point that variations in the contour of the backing rolls are controlled within such limits as to substantially prevent buckling or wrinkling of the thin material passed between the Working rolls, such as would be consequent upon variation of the contour of the backing rolls in the several stands.

11. A mill for producing thin, wide, rolled material of substantially uniform thickness, comprising a plurality of stands having working rolls and backing rolls of larger diameter, the mill operating to reduce the material to such thinness that its direction of travel between continuous stands could not be controlled by side guides, and anti-friction bearings for the necks of the backing rolls. whereby the contour of the backing rolls in a stand is not varied by roll neck heating to such an extent as to interfere with the proper direction of the material in a substantially direct line to a succeeding stand, the stands being arranged to successively act on the material.

12. A rolling mill comprising a series of stands of rolls arranged to successively en gage a piece of material to be rolled, each stand being composed of working rolls, backing rolls of larger diameter, and means for applying power to the working rolls, said mill defining successive passes of such width and eii'ective for taking such drafts that the product of the mill is of such width and thinness that slight variations of roll contour such as would be due toivariation arising from change .of temperature of the backing roll necks would buckle or wrinkle the piece during its passage through the mill, and antifriction bearings for the backing rolls whereby such buckling or wrinkling is avoided.

13. A mill for rolling material of substantially uniform thickness comprising at least two working rolls provided with backing rolls of largerdiameter, the backing rolls having necks of suflicient size to withstand the rolling pressure. and being at least as large in diameter as the diameter of the working roll bodies, and anti-friction bearings for said backing roll necks, the diameter of the backing roll body relative to the diameter of the Working roll being such as to permit of using anti-friction bearings of suflicient size to withstand the rolling pressure, said antifriction bearings being of such character as to permit of rolling at speeds which are high relative tothose ordinarily employed.

14. A mill for rolling material of substantially uniform thickness comprising at least two working rolls provided with backing rolls of larger diameter, the backing rolls having necks of suflicient size to Withstand the rolling pressure and anti-friction bear ings for said backing roll necks, the anti-friction bearings having spaced bearing rollers and being of sufficient size to withstand the rolling pressure over a continued peroid of time, the diameter of the backing roll body 'relative to the diameter of the working roll being such as to friction bearings.

15. A mill for rolling sheet or strip like material of substantially uniform thickness permit of using such anticomprising a working roll of substantially uniform diameter in the body portion provided with a backing roll of larger diameter and anti-friction mounting for said backing roll, the backing roll being of suflicient diameter to permit of using an anti-friction mounting of a character to withstand the rolling pressures encountered and to operate for extended periods of time at speeds which are on the order of multiples of speeds commonly employed in the rolling of such material.

16. A mill for producing thin, wide, rolled material of substantially uniform thickness, comprising a plurality of stands having working rolls and backing rolls of larger diameter, the mill operating to reduce the material to such thinness that its direction of travel between continuous stands could not be controlled by side guides, and anti-friction bearings for the backing rolls, whereby the contour of the backing rolls in a stand is not varied by backing roll heating to such an extent as to interfere with the proper direction of the material in a substantially direct line to a succeeding stand, the stands being arranged to successively act on the material.

17. A mill for rolling sheet or strip-like material of substantially uniform thickness, comprising a working roll of substantially uniform diameter in the body portion, backing rolls of larger diameter and antifriction mounting for said backing rolls, the backing rolls having diameters more than twice the diameter of the working rolls, whereby excessive crown in the product is avoided, and the backing rolls being also of sufficient diameter to permit of using an antifriction mount ing of a character to withstand the rolling pressures encountered and to operate for extended periods of time at speeds which are on the order of multiples of speeds commonly employed in the rolling of such material.

In testimony whereof I have hereunto set DISOLAI MER 1,779,195.Abram P. Steckel, Youngstown, Ohio. METHOD AND APPARATUS FOR ROLLING THIN SHEETLIKE MATERIAL. Patent dated October 21, 1930. Disclaimerfiled September 23, 1932, by the assignee, The Cold Metal Process Company. Hereby disclaims from the scope of claims 1, 2, 5, 9, and 10, limiting the rise in temperature of the backing roll necks by limiting the mill speeds to those employed prior to my invention for rolling such material.

Hereby disclaims from the scope of claims 6, 11, 12, 14, and 16 any mill having backing roll bearings of a character to limit the mill speeds to those employed prior to my invention for rolling such material. 7

[Ofiicial Gazette October 18, 1932.] 

